Source Sans Pro: Adobe's First Open Source Type Family

Adobe’s legacy in type technology

Adobe has come a long way since its early days
in which the specification for the PostScript Type 1 font format
was a closely-guarded trade secret leading up to the “font
wars.” Since this specification was begrudgingly published in
1990, Adobe has been more proactive in publicly releasing tools for
developing and producing high-quality type. Subsequently, Adobe
collaborated with Microsoft on the OpenType
standard, which was later made an open standard for type technology
as the Open Font Format: a free, publicly available standard
(ISO/IEC 14496-22:2009). In connection with this, Adobe has shared
its tool set for building OpenType fonts as the Adobe Font Development Kit for OpenType (AFDKO).
Although these tools are not open source, they can be used freely
and have been downloaded by thousands of users. Additionally, tools
such as FontLab Studio and FontMaster make use of AFDKO code for
building fonts. I believe that the world of type design and
typography has benefited greatly from Adobe’s contributions
in the arena of type technology. In adding to this legacy, I am
proud to announce that today marks another milestone as Adobe makes
yet another type resource freely available by releasing the Source
Sans Pro family as our first-ever open source type family.

Adobe’s open source contributions have not only been
limited to the realm of type. In recent years, Adobe has been
publishing more specifications and creating more open source tools.
In fact, Adobe has partnered with SourceForge to maintain many of
our projects on the Open@Adobe portion of that site. As more platforms and
applications are being developed at Adobe as open source software,
our type team has been fielding more frequent requests for type for
these environments. Although there are many open source type
families currently available, we felt that our applications would
benefit from a typeface tailored to their specific needs and that
this would be an opportunity for us to make a useful contribution
that would benefit Adobe, the open source community, type
developers, as well as anyone who uses type.

The brief & development

The primary need for type in Adobe’s open source
applications has thus far been for usage within user interfaces. A
second environment of perennial interest to Adobe is the realm of
text typography. Thus the immediate constraints on the design were
to create a set of fonts that would be both legible in short UI
labels, as well as being comfortable to read in longer passages of
text on screen and in print. In thinking of typeface models that
accomplish these tasks well, I was drawn to the forms of the
American Type Founders’ gothics designed
by Morris Fuller Benton. In particular, I have
always been impressed by the forms of his News Gothic and Franklin
Gothic, which have been staples for typographers since their
introduction in the early twentieth century. While keeping these
models in mind, I never sought to copy specific features from these
types. Instead, I sought to achieve a similar visual simplicity by
paring each glyph to its most essential form.

News Gothic type specimen from the American Type Founders’
Specimen Book and Catalogue, 1923. Actual Size.

During the development process, I was fortunate to be able to
work with application developers who deployed beta versions of what
would become Source Sans in the environments for which they were
intended. In fact, preliminary versions of the design have already
shipped with a couple of Adobe open source projects. A very early
version of the type family has been included in the Strobe Media Playback platform, using the name Playback
Sans. More recently, the WebKit-based code editor, Brackets, has featured
updated versions of the Source Sans fonts in its user interface, as
well as on its home page. Having real world testers, I was able to
receive recommendations on ways I could improve the design. One
particular feature that came about due to user feedback is the
treatment of the lowercase l. To fully differentiate it from the
uppercase I, I gave the default glyph for this letter a tail, even
though it is uncharacteristic for this particular type style. For
usages where this level of distinction is not required, there is an
alternate, simple lowercase l (without the tail) accessible via
stylistic alternates or by applying a stylistic set.

Differences between commonly confusable characters: 1, I, and
l.

About the fonts

We realize that the majority of users interested in this project
will likely only want the fonts. For this purpose, there is a
Source Sans font package that includes just
these resources. The family currently includes six weights, from
ExtraLight to Black, in upright and italic styles. The fonts offer
wide language support for Latin script, including Western and
Eastern European languages, Vietnamese, pinyin Romanization of
Chinese, and Navajo (an often overlooked orthography that holds
some personal significance for me). These fonts are the first
available from Adobe to support both the Indian rupee and Turkish
lira currency symbols. Besides being ready for download to install
on personal computers, the Source Sans fonts are also available for
use on the web via font hosting services including Typekit, WebInk, and Google Web Fonts. Finally, the Source Sans family will
shortly be available for use directly in Google documents and Google presentations. Full glyph complement specimens (793K) are available in the
Adobe type store along with informational pages for each style.

In making these fonts open source, it is important to us to make
all the source files we used in their production available
so that they can be referenced by others as a resource on how to
build OpenType fonts with an AFDKO workflow. The full package of
source files can be obtained from the Source Sans download page on SourceForge. As part
of this ongoing project, we are publishing a roadmap of features
that we plan to implement in the near future. At present, this
includes items such as expanding the fonts to provide Cyrillic and
Greek support, as well as producing a monowidth version of the
Source Sans design.

Monowidth variant of Source Sans (work in progress)

In addition to making these files available as a learning
resource, we are eager that this project will become an undertaking
in which we can collaborate with others in the design community. We
hope that if any of you want to build upon these assets that you
will consider coordinating with us to help add features and
increase language support for this family. In fact, this project
has already been a concerted effort (as is so much of type design).
I am grateful to Robert Slimbach for his guidance throughout this
project — the design would not have been anywhere near as
good without his input. I am indebted to Miguel Sousa who ensured
that all of my files were fit for publication. I would also like to
thank Ernie March for his work in testing and vetting the font
files. We hope that you find these fonts useful in your work and we
look forward to seeing the interesting ways in which you employ
them in your designs.